Stitch-forming mechanism for sewing-machines



I. H. IVIOFFATT. STITCH FORMING. MECHANISM FOR SEWING MACHINES.

APPLICATION FILED IUNE I6. i915.

Patented Mar. 23,1920.

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STITCH FOHNIING NIECHANISM FOR SEWING MACHINES. APPLIcATloN men JUNE la. |915.

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\ /O l Ooo I. II. MOFIFATT. STITCH FoRMlNG MECHANISM FUR SEWING MACHINES.

APPLICATION FILED IUNE I6 I9I5.

Patented Mar. 23, 1920.

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I. II. MIIFFAII.

STITCH FORIVIING MECHAYNISNI FOR SEWING MACHINES.

APPLICATION FILED IIINE I6, Iers.

1,334,626. I Patented Mar. 23,1920.

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JAMES R. MOFFATT, F CHICAGO, ILLINOIS, AFSSIGNOR- IDD UNIOSN SPEIAD MACHINE COMPANY, F CHICAGO, ILLINIS, 1i. CORPRAIIUN C11? ILLINOIS.

Specification of Letters Patent.

Patented 111:11". 23, 1920.

Application filed June 16, 1915. Serial No. 34,425.

/'o (M who/a 'it may concern:

lle it known that I, learns it; Morrfir'i, a citizen oit the United States, residing at Chicago, in the county of Clock, State olf Illinois, have invented certain new and use-tui Improvements in Stitch Forming` Mechamsm for Sewing-Machines, oit which the iol:

lowing support.

in object of the inifentio-n is to provide a cross thread laying` mechanism, wher-ein the thread laying implement is actuated by a positively operated train oil'f :mechanism including as one of its elements the auxiliary presser bar.

A 'further object oit the invention is to provide a machine ol the above character having tivo thread layingimplements with devices whereby said implements may be operated simultaneously in opposite directions lirom the same actuating' arm carried by the auxiliary presser bar.

These and other objects will in part be ohviorls and will in part be hereinafter more` itnlly disclosed.

Inv the drawings,` which show by way ot illustration one embodiment oi the invention,-

Figure 1 is a rear view `of a stavingmachine embodying my improvements;

Fig. 2 is an end elevation ot the saine, certain ot the parts being1 omitted to avoid confusion;

Fig. 3 is a. vieiv partly min section and partly in top plan, showing` a portion ot the ivork support, presser toot, the needle bar` the thread laying' devices and the means tor operating the same 'trom the auxiliary presser bar;

Fig. 1 is a similar view showing the thread laying lingers in diiierent positions;

Fig. 5 is a detail, partly in section andA partly in rear elevation, showing the manner of supporting the thread layingl fingers on the presser bar;

Fig. 6 is a detail, showing one ot the connections betvveen the main presser' bar and the tnxiliary presser bar; y

l? 7 is a sectional vieiv on the line 7-T oi Fig. 6;

Fig. 8 is a sectional view on the line 8--8 ot Fig. et;

Fig'. 9 is a detail in plan, shmvinp,I the operating rocker tor one of the thread laying ingers;

Fig. 10 is a similar View, showing' the rocker tor the other thread laying` finger;

F 11 is a vievlT more or less diagrammatic, showingi the train of mechanism hetween the thread laying` fingers and the-horizontal operating shaft at the rear oi the machine; y

Fig. 12 a vievv showing' diagrammatically the position ot the needles and the thread laying' iingers on one stroke ot the needles;

Fig. 13 is a similar vien", showing the position olf the thread layingr fingers on the next stroke o1 the needles; and

Fig. 14 is a diagrammatic view, showing` the position oit the cross threads relative to the needle threads in the finished seam.

I have shovvn my improved thread laying mechanism as applied to a sewing machine having a bed 1, which carries a Work support 2. ai standard 3 is also supported on the bed and carries an overhanging arm il. A needle bar reciprocates in the supporting head 6 at the forward end oi' the overhang-ing arm il. This needle bar is reciprocated by a needle lever 7, which is oscillated by aneccentric strap 8 cooperatingl with an eccentric on the main shaft 9. The needle bar 5, as herein shown, is provided with three needles 10, 11 and 1'2. Coperatinn with the needles beneath the Work support is a single looper 18, see Figs. 12 and 13. This three needle stitching mechanism is Well known in the art and further description thereof is not thought necessary.

The material. to be stitched is iEed to the needles by a feed dos` 14, Which is operated in the usual Way. Cooperating with the feed dop; 1-1 is a presser' toot 15, which is carried by a presser bar 16. This presser bar is mounted so as to slide `lreely in the supporting head 6 and may be raised by` a hand lever 17 or a lever 18 which may be connected to a suitable treadle. A spring- 19 31 engages this pin 30 operates to hold the presser bar on the work support.

Cooperating with the needles, as herein shown, are two thread carrying fingers 2O and 21. The thread carrying linger 2O is clamped to an arm 22 which projects laterally from a rocking frame Said linger is held on the arm by a suitable set-screw The thread llaying linger 21 is carried by an arm 25 which projects laterally from a roeking frame 26 and said finger is secured to the arm by a similar set-screw. These rocking frames 23 and 26 are mounted one above the other on the presser bar 16.- Said presser bar is provided with a bearing collar 27 located directly above the presser foot and the rocking frame 26 rests thereon. A collar 2S carried by the presser bar 16 and secured thereto by a set screw, engages the upper face of the rocking frame 23 for the thread linger 20.l The rocking frame 23 has a second arm 29, which carries a pin 30. A link at one end and at its other end said link freely engages a pin carried by an arm 33 lixed to the auxiliary presser bar 34. The rocking frame 26 .is provided with a second projecting arm 35, which carries a pin 36. A link 37 engages at one end this pin 36 and at its other end said link engages the pin 32-carried by the arm 33. Said pin 32 is clamped to the arm 33 by a set screw 38 and said pin has a head 39 .in its lower end, so that the links 31 and 3T freely engage thel pin and are held thereon.

rlhe auxiliary presser bar 34 is mounted so as to reciprocate and also oscillate in the supporting head 6 :of the machine. Said main presser bar 16 has two laterally projecting upper and lower guiding arms 40 and 41 which are lixed to the presser bar and these arms at their rear ends are forked, as at 42, the fork of the arm 41 strad dling a block 43 which is freely mounted on the auxiliary presser bar and said 'block is provided with a flanged head 44 to prevent the same from falling through the fork. The fork of the arm 40 also straddles a similar block. A collar 45 is rigidly attached to the auxiliary presser bar directly above the block 43. These arms 40 and 41 prevent the main presser bar 16 from oscillating in its supporting bearings and the fixed collar 45 insures that the auxiliary presser guide bar is lifted with the main presser bar 16. The block 43 has a free connection with the auxiliary presser bar and permits the latter to oscillate. Said auxiliary presser bar is provided with a laterally projecting arm having' a ball stud 46. A link 47 engages this ball stud at one end and at its other end engages a ball stud 48 carried by a crank pin fixed to the shaft 49. The shaft 49 is a horizontal shaft and is mounted in the bearings 50 and 51 at the rear of the machine. Said shaft 49 carries threads are indicated a rearwardly projecting arm 52 which also has a ball stud for the eccentric strap 53.

rlhe eccentric strap 53 cooperates with an eccentric on a stub-shaft mounted in a bearing 54 carried by the standard 3 and this stub-shaft carries a gear wheel 55 which meshes with a gear wheel 56 on the main shaft 9. The gear wheel is double the size of the gear wheel 56, so that the stub-shaft is rotated once for every two rotations ol' die main shaft. This rotation of the stub-shalt through the eccentric strap 53 oscillates the shaft 49 giving one complete oscillation thereto for each rotation of the stub-shaft. As the shaft 49 oscillates the link 4T will oscillate the auxiliar7 presser bar 34 and this in turn will oscillate the arm 33 at the lower end thereof. The oscillations of the arm 33 will be imparted through the linhs 31 and 3i' to the rocking frames 23 and 26, respectively. inasmuch as the connections to these rocking frames are on opposite sides of the longitudinal axis of the presser bar. said thread lingers carried by the rocking frames will be moved respectively in opposite directions.

l have shown diagrannnatically .in llig. 12 the needles raised and the looper in its forward position. The thread lingers 2U and and 21 are retracted and the threads l and of these thread lingers respeeliivelj extend from the thread lingers to the eppo site sides of the seam where they were prcriously interlocked with the needle threads. ril`he needles on their downward movement pass in front of these threads (1 3). r1`hc thread lingers 20 and 21 uiove forward to the position shown in Fig. 13, so that, when the needles are again at the upper end of their stroke, the threads a. and Z1 of; th x thread lingers are crossed in the opposite direction in rear of the needles, so that on the next descent of the needles they will pass again in front of the needles.

It will thus be seen that the threads are laid in front of the needles on a movement of the thread lingers in one direction for each complete stroke of the needles, so that in the resulting seam the threads are crossed between each set of needle puncturcs, as clearly shown inF 14, wherein the needle at c, (Zand c, respectively, for the needles 10, 11 and 12.

From the above description. it will be apparent that I have provided a positive train of mechanism for actuating the thread lingers which includes as one of its elements the auxiliary presser bar, and this great/lj` `simplifies the construction of the mechanism for actuating' the thread lingers, and that the lingers are supported by and movable with the presser bar, this allowing' the foot to be raised without ii'iterfering with said lingers. Furthermore, the connecting parts are rela tively short in length and free from lateral lll) jll)

1 ,lss-aces vibration during the actuation of the inachine, and, therefore, the machine is particularly adapted for high speed stitching.

ilihile ll have shown tvvo thread fingers, it will be obvious that my improved cross tln'ead laying mechanism may be applied to a stitching mechanism wherein one cross thread laid back and forth for engagement with the needle threads. it is also obvious that minor changes in the details of con struction and arrangement of parts may be made without departing from the spirit of the invention, as set forth in the appended claims.

y Having thus described my invention, what l claim as new and desire to secure by lietters Patent, is:

l. The combination with a work support, a presser foot, a main presser bar carying said presser foot, needles, vmeans for reciprocating said needles, of cross thread` laying mechanism located above the work support including a thread carrying linger for continuously guiding the cross thread, a supporting arm for said finger, said arm being mounted to oscillate about the axis of the presser bar and movable up and down with said presser bar, a vertical shaft located eitterior of the presser `bar and movable up and down with said presser bar, means for oscillating said vertical shaft, and means for connecting said vertical shaft to said supporting arm for oscillating` said thread laying finger.

2. The combination with a work support, a presser foot, a main presser bar carrying said presser foot, needles, means for reciproating said needles, of cross thread laying mechanism located above the work support including a thread laying linger for continuously guiding the cross thread, an arm supporting said thread laying finger, said arm being mounted to oscillate about the axis the presser bar and movable up and down with said presser bar, an auxiliary presser bar movable up and down with said main presser bar, means for oscillating said al'ixiliary presser bar, and means for connecting said auxiliary presser bar with said arm for oscillating the latter.

The combination with a work support, a presser foot, a main presser bar carrying said. presser foot, needles, means for reciprocating said needles, of cross thread laying mechanism located above the work support in cluding a thread laying finger for continuously guiding the cross thread, a rocking frame carrying said finger, said frame being mounted to oscillate abouty the axis of the presser bar and movable up and down therewith, an auxiliary presser bar movable up and down with said main presser bar, a horiaontal shaft, means for oscillating said shaft, means for connecting said horizontal shaft to said auxiliary presser bar for oscillating the latter, and means for connecting the lower end of said auxiliary presser bar with said rocking frame for oscillating thc thread. laying finger.

a. The combination with a work support, a presser foot, a main presser bar carrying said presser foot, needles, means for reciprocating said needlesof cross thread laying mechanism located above the work support incliilding thread laying fingers, a separate supporting shank for` ear-h finger, said Shanks being mounted to oscillate freely on the presser bar and move up and down therewith, an auxiliary presser bar moving up and down with said main presser bar, an arm extending laterally from said auxiliary presser bar, links connecting said arm rc spectively withthe supporting shanks for the thread fingers on opposite sides of the presser bar, and means for oscillating said auxiliary presser bar.

5. The combination with a work support, a presser foot, a main presser bar carrying said presser foot, needles, means for reciprocating said needles, of cross thread lay-- ,ing mechanism located above the work support including thread laying fingers, a separate supporting shank for each finger, said shanks being mounted to oscillate freely on the presser bar and move up and down therewith, an auxiliary presser bar moving up and down with said main presser bar, an arm extending laterally from said auxiliary presser bar, links connecting said arm respectively 'with the supporting Shanks for the thread lingers on opposite sides of the presser bar, a horizontal shaft, an arm pro-` jecting downwardly from said shaft, a second arm carried by the auxiliary presser bar, and a link for connecting the arm of the horizontal shaft with the arm of the auxiliary presser bar.

6. The combination with a work support, a presser foot, a main presser bar carrying said presser foot, needles, means for reciprocating said needles, of cross thread laying mechanism located above the work support including thread lingers located on opposite sides of the needles, an annular supporting shank for each thread linger, said Shanks being mounted to oscillate on the presser foot, a bearing washer on which said Shanks rest, a collar secured to the presser bar above said shanks, each shank having an arm projecting outwardly therefrom, said arms being located on opposite sides of the center of the presser bar, an auxiliary presser bar connected to said main presser bar and movable upand down therewith, an arm projecting laterally from said auxiliary presser bar, a headed pin carried by said arm, links freely engaging said pin and pivoted respectively to the arms carried by said shanks, and means for oscillating said auxiliary presser bar.

li (i 7. The combination with a work support, a presser foot, a main presser bar carrying said presser foot, needles, means for reciprocating said needles, of cross thread laying mechanism located above the work support including a thread laying finger foreontinuously guiding the cross thread, an arm supporting said thread laying finger, said arm heilig' mounted to oscillate about the axis of the presser bar and movable up and down with said presser bar, an auxiliary presser bar, means for oscillating said auxiliary presser bar, and means for connecting said auxiliary presser bar with said arm for oscillating the latter.

8. The combination of a work support, a needle bar, a plurality of needles carried thereby, a presser bar, a presser foot, an auxiliary presser bar and cross thread lay- .ing mechanism including thread guiding fingers mounted on the presser bar and movable up and down therewith, said fingers being respectively disposed on opposite sides of the needles, means for oscillating said auxiliary presser bar and ing said thread guiding auxiliary presser bar.

9. The combination of a work support, a needle bar, a plurality of needles carried thereby, a presser bar, a presser foot, an auxiliary presser bar and cross thread laying mechanism including thread guiding fingers mounted on the Dresser bar and movable up and down therewith, said lingers being respectively disposed on opposite sides of the needles, means for oscillating said auxiliary presser bar and means for operating said thread guiding fingers from said auxiliary presser bar, said thread guiding fingers being so disposed as to cross the line of seam in different horizontal planes.

In testimony whereof, I afiix my signature in the presence of two witnesses.

JAMES R. IVIOFFi-XT' means for operatfingers from said Witnesses z S. GEORGE TATE, A. F. BREDSHALL. 

